Various kinds of electric plug locking devices exist to prevent unsupervised use of electrical equipment and to appliances. Exemplary of such is the one disclosed in U.S. Pat. No. 4,488,764. This plug locking device entirely encloses an electrical plug, including its body and terminals, within a device cavity that has an opening through which an electrical cord extends. Access to the cavity is controlled by a cavity cover with a key lock. When the plug locking device is unlocked to allow use of the plug, the plug is completely removed.
Distinct disadvantages exist with this type of plug locking device. For example, a key must be readily available to unlock it. If the key is off the premises, delay occurs in accessing the plug. If the key is misplaced, a new key must be made. Once the device is unlocked, it too may be misplaced.
Another plug locking device, as disclosed in U.S. Pat. No. 4,865,557, eliminates the need for a key by permanently locking the plug into a chamber with a post and cap latch. However, the post must be severed to permit the device to open and release the plug. Such a plug locking device, therefore, can be used only once.
Thus, there exists a need for a plug locking device to secure an electrical plug from use which remains affixed to the plug even in an unlocked position, which does not necessarily require the use of a key, and which is capable of repeated use. Accordingly, it is to the provision of such an improved plug locking device that the present invention is primarily directed.